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Making a good old metal pencil cap
Pencils have some advantages over ball pens. They don't dry out, whatever you write with it does not bleach in the sun and most importantly they work in winter. The later might be a Canadian problem but it can be really annoying when you want to write down the phone number of a friend and the ball pen stops after the first digit because the ink has frozen. This happens even if you had the ball pen in your jacket. The ink at the tip between the ball and the sides freezes as soon as it touches cold paper (e.g below -15'C). Pencils don't have this problem they just work.
One can get nice pencils with a clip to carry in the shirt pocket but I do actually prefer to have one in the pockets of my pants. The problem with that is that the pencil leads tend th break off when you carry it this way. Once upon a time one could buy nice brass caps to protect the pencil leads but they are almost unknown today. I don't think they are produced anymore. I have found some plastic caps but the problem with them is that they are not elastic and you can not adjust their size. Every pencil manufacturer seems to produce slightly different pencil sizes. There is only a difference of 0.5mm - 1mm in diameter but that is the difference between a loose cap that falls off and a snug fit.
A good protective pencil cap needs to be made of metal and it has to have a slot on the side such that it is possible to adjust the size a bit. It should be a metal with a bit of a spring effect, not too soft. A snug fit is important. Here is a nice pencil cap that I designed recently using the bottom of a chocolate powder tin. Any tin will work as long as it is not painted. It needs to be just plain tin coated steel to allow you to solder the metal at the tip.
Use the metal from a coffee or chocolate powder tin
Bend it and solder the sides of the tip
Painted green like an alligator
In the above pictures you can see how I made this pencil cap. The most important step is to first produce a paper model to get the size right. Unpainted steel tins can be soldered quite easily since the material is steel coated with a bit of tin. The sides of the tip of the pencil cap can be soldered with a normal soldering iron and lead free solder to form a closed round tip. I recommend to bend over and fold the metal on the open end of the cap to not have any sharp edges there.
From the sides it looks a little bit like an alligator so I decided to paint it green.
It's very useful to have a small pencil in your pocket.
© 2004-2023 Guido Socher